Known as a conventional laser processing method is one which irradiates a planar object to be processed with laser light while locating a converging point at the object so as to form a modified region within the object along a line to cut the object (see Patent Literature 1, for example). Such a working method for cutting applies an external stress to the object formed with the modified region along the line to cut, for example, so as to cut the object into a plurality of chips from the modified region acting as a start point.    Patent Literature 1: Japanese Patent Application Laid-Open No. 2004-343008